Inferences on the population structure and colonization process of the invasive oriental fruit fly, Bactrocera dorsalis (Hendel)

Abstract

The phytophagous insects of the Tephritidae family offer different case histories of successful invasions. An example is Bactrocera dorsalis sensu stricto, the oriental fruit fly which has been recognized as a key pest of Asia and the Pacific. It is known to have the potential to establish adventive populations in various tropical and subtropical areas. Despite the economic risk associated with a putative stable presence of this fly, the genetic aspects of its invasion process have remained relatively unexplored. Using microsatellite markers we have investigated the population structure and genetic variability in 14 geographical populations across the four areas of the actual species range: Far East Asia, South Asia, Southeast Asia and the Pacific Area. Results of clustering and admixture, associated with phylogenetic and migration analyses, were used to evaluate the changes in population genetic structure that this species underwent during its invasion process and establishment in the different areas. The colonization process of this fly is associated with a relatively stable population demographic structure, especially in an unfragmented habitat, rich in intensive cultivation such as in Southeast Asia. In this area, the results suggest a lively demographic history, characterized by evolutionary recent demographic expansions and no recent bottlenecks. Cases of genetic isolation attributable to geographical factors, fragmented habitats and/or fruit trade restrictions were observed in Bangladesh, Myanmar and Hawaii. Regarding the pattern of invasion, the overall genetic profile of the considered populations suggests a western orientated migration route from China to the West.

Characterization and evaluation of microsatellite markers in a strain of the oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae), with a genetic sexing character used in sterile insect population control

“…The tested wild population showed a high level of genetic variability comparable with the previously characterized populations from various geographical origins (Aketarawong et al, 2007). In addition, the genetic diversity (Na = 11.36, HO = 0.52, and HE = 0.83) was especially similar to a previously characterized population located in the nearby (< 100 km) Ratchaburi Province (Na = 10.14, HO = 0.53, and HE = 0.86; Aketarawong et al, 2011).…”

“…The samples were preserved in 95% ethanol and stored at -20°C before DNA extraction. Genomic DNA was extracted from individual flies as detailed in Aketarawong et al (2007).…”

“…Its geographical distribution is expanding in tropical and subtropical regions from Asia to a potentially much larger range (CABI/EPPO, 1998). The oriental fruit fly is invasive due to its apparent wide host range, high fecundity, dispersal capacity, and bioclimatic adaptive abilities (Aketarawong et al, 2007;Stephens et al, 2007). Integrated pest management (IPM) of the oriental fruit fly coordinates the use of pest and environmental information and available pest control methods to prevent economic losses whilst hopefully reducing negative effects to the environment.…”

“…In recent years, high resolution microsatellite markers for B. dorsalis were designed (Aketarawong et al, 2006). Many of these markers revealed high levels of polymorphism in different geographical populations, either at micro-or macro-geographical levels (Aketarawong et al, 2007). Subsequently, they were utilized for the evaluation of AW-IPM using SIT for fruit fly control programmes (Aketarawong et al, 2011).…”

Analysis of olive fly invasion in California based on microsatellite markers

“…Microsatellites are particularly informative in the study of recent population phenomena, such as biological invasions (Bruford and Wayne, 1993;Schlö tterer and Pemberton, 1994;Tautz and Schlötterer, 1994). Moreover, they have been successfully used in the analysis of population structure of different Tephritidae species, such as Ceratitis capitata (Bonizzoni et al, 2001;Gasperi et al, 2002), Bactrocera dorsalis (Aketarawong et al, 2007) and B. tryoni (Yu et al, 2001;Gilchrist et al, 2004). In the case of C. capitata, they have provided guidance in establishing the source of recent invasions in different parts of the world (Meixner et al, 2002;Bonizzoni et al, 2004).…”